With midterm elections just around the corner, President Barack Obama is sharpening his populist rhetoric against the GOP.

In his weekly address, Obama accused Republicans of backing big new tax breaks for millionaires while cutting transportation grants that have created jobs.

He also spotlighted the looming expiration of transportation programs, potentially putting projects on hold.

"If Congress fails to act, nearly 700,000 jobs would be at risk over the next year," he said. "That’s why I put forward a plan to rebuild our transportation infrastructure in a more responsible way. It would support millions of jobs across the country. And we’d pay for it without adding to the deficit by closing wasteful tax loopholes for companies that ship jobs overseas."

Republicans are proposing to cut a specific transportation grant program by 80 percent, he said.

"They can’t say it’s to save money, because at the very same time, they voted for trillions of dollars in new tax cuts, weighted towards those at the very top," he said.

"Think about that. Instead of putting people to work on projects that would grow the economy for everyone, they voted to give a huge tax cut to households making more than $1 million a year."

The House GOP budget authored by Budget Chairman Paul D. Ryan, R-Wis., proposes keeping tax revenue flat by cutting the top income tax rate from 39.6 percent to 25 percent, among other changes, and paying for it by eliminating tax breaks. That would slash tax bills for many millionaires.

It's not clear where Obama gets his figure that Republicans are proposing "trillions" in new tax breaks, given that Ryan's budget is revenue neutral.

Republicans since adopting the budget have, however, turned around and proposed hundreds of billions in permanent extensions of popular business tax breaks. Obama has threatened to veto the first bill.